When you create a new database, BookCAT will use a default 5 star rating system like this:

This can (of course!) be customized. Simply open the edit window, and load a new image into the Rating image field:

You can use any GIF image as long as it is less than 100 x 100 pixels in size.

BookCAT v9 ships with these images:

You can use any of these, or your own images.